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- /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #pragma once
- #include <AK/Types.h>
- #include <Kernel/Arch/x86/CPUID.h>
- namespace Kernel {
- class MSR {
- uint32_t m_msr;
- public:
- static bool have()
- {
- CPUID id(1);
- return (id.edx() & (1 << 5)) != 0;
- }
- MSR(const MSR&) = delete;
- MSR& operator=(const MSR&) = delete;
- MSR(uint32_t msr)
- : m_msr(msr)
- {
- }
- [[nodiscard]] u64 get()
- {
- u32 low, high;
- asm volatile("rdmsr"
- : "=a"(low), "=d"(high)
- : "c"(m_msr));
- return ((u64)high << 32) | low;
- }
- void set(u64 value)
- {
- u32 low = value & 0xffffffff;
- u32 high = value >> 32;
- asm volatile("wrmsr" ::"a"(low), "d"(high), "c"(m_msr));
- }
- };
- }
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